1. Field of the Invention
This invention relates to the art of dyeing of cellulose-containing textiles. Specifically, it relates to concentrated aqueous solutions containing both dispersants and sequestrants which are used in pretreatment and dyeing to prevent precipitate formation.
2. Description of the Prior Art
For the pretreatment and dyeing of textiles consisting of cellulose or containing cellulose, two types of agents are used to prevent solids precipitation. Complex builders such as amino carboxylic acids, the structurally analogous phosphonic acids, as well as hydroxyalkane polyphosphonic acids are used as sequestrants for alkaline earth and heavy metals (compare European Pat. No. 718,981). With these metal ions, these complex builders produce soluble complexes so that precipitation is prevented. They, furthermore, have the ability to redissolve already existing precipitates.
The second type agent is exemplified by polymers or copolymers of acrylic acid which are used as dispersants for difficult to dissolve components such as, for example, calcium pectinates, which occur during boiling and bucking processes as well as in dyeing liquors. (Compare, for example, German application No. 29 26 098). These complexing and dispersing agents were previously each used in the form of approximately 25 to 60 percent solutions of their sodium salts. Free acid components (as a result of incomplete neutralization) could be present.
As part of the rationalization process, it would be advantageous to mix the two agents together as a single concentrated solution thus achieving simple and convenient metering. However, it is not possible to dissolve mixtures of the sodium salts in water together in the desired cncentration since these components "salt each other out" at these concentrations. Solutions with concentrations of up to 10 percent are stable. A combined solution at this concentration is not possible either when the free acids are used.
The purpose of this invention was a combined liquid packaging of above-mentioned complexing and dispersing agents in an aqueous solution with as high a concentration as possible.